utp_templates.h

/*
 * Copyright (c) 2010-2013 BitTorrent, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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 * THE SOFTWARE.
 */

#ifndef __TEMPLATES_H__
#define __TEMPLATES_H__

#include "utp_types.h"

#if defined(POSIX)
/* Allow over-writing FORCEINLINE from makefile because gcc 3.4.4 for buffalo
   doesn't seem to support __attribute__((always_inline)) in -O0 build
   (strangely, it works in -Os build) */
#ifndef FORCEINLINE
// The always_inline attribute asks gcc to inline the function even if no optimization is being requested.
// This macro should be used exclusive-or with the inline directive (use one or the other but not both)
// since Microsoft uses __forceinline to also mean inline,
// and this code is following a Microsoft compatibility model.
// Just setting the attribute without also specifying the inline directive apparently won't inline the function,
// as evidenced by multiply-defined symbols found at link time.
#define FORCEINLINE inline __attribute__((always_inline))
#endif
#endif

// Utility templates
#undef min
#undef max

template <typename T> static inline T clamp(T v, T mi, T ma)
{
	if (v > ma) v = ma;
	if (v < mi) v = mi;
	return v;
}

#if (defined(__SVR4) && defined(__sun))
	#pragma pack(1)
#else
	#pragma pack(push,1)
#endif


namespace aux
{
	FORCEINLINE uint16 host_to_network(uint16 i) { return htons(i); }
	FORCEINLINE uint32 host_to_network(uint32 i) { return htonl(i); }
	FORCEINLINE int32 host_to_network(int32 i) { return htonl(i); }
	FORCEINLINE uint16 network_to_host(uint16 i) { return ntohs(i); }
	FORCEINLINE uint32 network_to_host(uint32 i) { return ntohl(i); }
	FORCEINLINE int32 network_to_host(int32 i) { return ntohl(i); }
}

template <class T>
struct PACKED_ATTRIBUTE big_endian
{
	T operator=(T i) { m_integer = aux::host_to_network(i); return i; }
	operator T() const { return aux::network_to_host(m_integer); }
private:
	T m_integer;
};

typedef big_endian<int32> int32_big;
typedef big_endian<uint32> uint32_big;
typedef big_endian<uint16> uint16_big;

#if (defined(__SVR4) && defined(__sun))
	#pragma pack(0)
#else
	#pragma pack(pop)
#endif

template<typename T> static inline void zeromem(T *a, size_t count = 1) { memset(a, 0, count * sizeof(T)); }

#endif //__TEMPLATES_H__